Alignment sleeve assembly and fiber optic adapter

ABSTRACT

A fiber optic adapter, including: a mating retainer; an alignment sleeve received in the mating retainer, a ferrule of a fiber optic connector being adapted to be inserted into the alignment sleeve through an insertion port of the fiber optic adapter; and an adjustment element configured to adjust a circumferential angle of the alignment sleeve relative to the mating retainer to a predetermined circumferential angle and hold the alignment sleeve at the predetermined circumferential angle relative to the mating retainer. The adjustment element may adjust the circumferential angle of the alignment sleeve with respect to the mating retainer to the predetermined circumferential angle, for example, at which the fiber insertion loss of the coupled connectors is minimal, and hold the alignment sleeve at the predetermined circumferential angle. In this way, it may improve the alignment accuracy of the coupled connectors.

This application is a Continuation of U.S. patent application Ser. No.15/574,389, filed on 15 Nov. 2017, which is a National Stage Applicationof PCT/CN2016/082021, filed on 13 May 2016, which claims benefit ofSerial No. 201510247621.4, filed on 15 May 2015 in China and Serial No.201520319609.5, filed on 15 May 2015 in China and which applications areincorporated herein by reference. To the extent appropriate, a claim ofpriority is made to each of the above disclosed applications.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an alignment sleeve assembly and afiber optic adapter comprising the alignment sleeve assembly.

Description of the Related Art

In the prior art, a fiber optic adapter (for convenience of description,herein take a single-fiber SC adapter as an example) generally comprisesan alignment sleeve, a mating retainer for receiving the alignmentsleeve therein and locking a pair of coupled fiber optic connectors, ahousing, a buckle type fixing clamp spring and a warranty buckle(optional).

In the prior art, there is machining error in the alignment sleeve, forexample, inner wall roundness of the alignment sleeve is not enough, andwall thickness of the alignment sleeve is not uniform. As a result, whenferrules of a pair of fiber optic connectors are inserted into thealignment sleeve of the fiber optic adapter from opposite ends of thealignment sleeve and coupled with each other, in addition to analignment error, which will lead to a connection loss, between fibercores of the coupled connectors, the alignment sleeve will also cause acertain alignment error, it will further increase the connection loss orincrease the connection loss uncertainty. For an individual alignmentsleeve, only when the alignment sleeve is located at a particularcircumferential angle, the connection loss caused by it is minimal.

In the prior art, for batch manufacturing, the particularcircumferential angle of each individual alignment sleeve correspondingto the minimum connection loss is apt to be different. Furthermore, thealignment sleeve is not positioned and fixed in the circumferentialdirection, and the alignment sleeve may rotate randomly. Therefore,minimizing the connection loss by positioned the alignment sleeve at theparticular circumferential angle is not recognized and well utilized yetby the existing design.

As for the fiber optic adapter in the prior art, the alignment sleevemay freely rotate in the mating retainer along the circumferentialdirection and have a certain degree of freedom in three directionsperpendicular to each other. Since the alignment sleeve has a certaintolerance, the connection loss of the coupled connectors has certainpolarity. That is, only when the alignment sleeve is positioned at theparticular circumferential angle, the coupled connectors may achieve theminimum insertion loss. However, in the prior art, the alignment sleevemay be rotated randomly. Thereby, the insertion loss of the entireoptical fiber interconnection system is not always kept in a state ofminimum loss. In other words, the random nature of the circumferentialangle of the alignment sleeve affects the total insertion loss of thefiber interconnection system. Such situation does not meet strictrequirements on ultra low insertion loss of optical fiberinterconnection system in future and requirements on the repeatabilityof the ultra low insertion loss after the fiber optic connectors aredecoupled.

SUMMARY OF THE INVENTION

The present invention has been made to overcome or alleviate at leastone aspect of the above mentioned disadvantages.

According to an object of the present invention, there is provided analignment sleeve assembly and a fiber optic adapter comprising thealignment sleeve assembly, in which an alignment sleeve may be adjustedto and fixed at a predetermined circumferential angle, at which thefiber optic insertion loss is minimal, with respect to a matingretainer. In this way, it improves the alignment accuracy of a pair ofcoupled fiber optic connectors.

According to an aspect of the present invention, there is provided afiber optic adapter, comprising: a mating retainer; an alignment sleevereceived in the mating retainer, wherein a ferrule of a fiber opticconnector is adapted to be inserted into the alignment sleeve through aninsertion port of the fiber optic adapter; and an adjustment elementconfigured to adjust a circumferential angle of the alignment sleeverelative to the mating retainer to a predetermined circumferential angleand hold the alignment sleeve at the predetermined circumferential anglerelative to the mating retainer.

According to an exemplary embodiment of the present invention, when thealignment sleeve is held at the predetermined circumferential anglerelative to the mating retainer, an alignment error between fiber coresof fibers, inserted into the alignment sleeve of the fiber opticadapter, of a pair of fiber optic connectors is minimal.

According to another exemplary embodiment of the present invention, whenthe alignment sleeve is held at the predetermined circumferential anglerelative to the mating retainer, a longitudinal slot in the alignmentsleeve is positioned at a predetermined orientation.

According to another exemplary embodiment of the present invention, theadjustment element is adapted to be sleeved on the alignment sleeve, anda radial protrusion is formed on an inner wall of the adjustment elementand adapted to be inserted into the longitudinal slot of the alignmentsleeve, so that the alignment sleeve is capable of being rotated withthe alignment element, and the circumferential angle of the alignmentsleeve relative to the mating retainer is capable of being adjusted byrotating the adjustment element.

According to another exemplary embodiment of the present invention, whenthe radial protrusion of the adjustment element is inserted into thelongitudinal slot of the alignment sleeve, the alignment sleeve isunable to be rotated in a circumferential direction relative to theadjustment element.

According to another exemplary embodiment of the present invention, whenthe radial protrusion of the adjustment element is inserted into thelongitudinal slot of the alignment sleeve, the alignment sleeve is onlyable to be rotated in a range of ±30 degrees in a circumferentialdirection relative to the adjustment element.

According to another exemplary embodiment of the present invention, whenthe radial protrusion of the adjustment element is inserted into thelongitudinal slot of the alignment sleeve, the alignment sleeve is onlyable to be rotated in a range of ±20 degrees in a circumferentialdirection relative to the adjustment element.

According to another exemplary embodiment of the present invention, whenthe radial protrusion of the adjustment element is inserted into thelongitudinal slot of the alignment sleeve, the alignment sleeve is onlyable to be rotated in a range of ±10 degrees in a circumferentialdirection relative to the adjustment element.

According to another exemplary embodiment of the present invention, theadjustment element is formed as a polygonal prism with a polygon crosssection; a positioning slot, corresponding to an outer profile of theadjustment element, is formed in the mating retainer; the adjustmentelement is adapted to be fixed in the positioning slot of the matingretainer, so as to hold the alignment sleeve at the predeterminedcircumferential angle relative to the mating retainer.

According to another exemplary embodiment of the present invention, theadjustment element is formed with multiple spline keys, and the matingretainer is formed with multiple spline slots; the multiple spline keysof the adjustment element are adapted to be fitted in the multiplespline slots of the mating retainer, so as to hold the alignment sleeveat the predetermined circumferential angle relative to the matingretainer.

According to another exemplary embodiment of the present invention, afirst circumferential angle mark is provided on an outer surface of theadjustment element, and a second circumferential angle mark is providedon the mating retainer; when the alignment sleeve is adjusted to thepredetermined circumferential angle by the adjustment element, the firstcircumferential angle mark of the adjustment element is aligned with thesecond circumferential angle mark of the mating retainer.

According to another exemplary embodiment of the present invention, thefiber optic adapter further comprises a housing in which the matingretainer are mounted; an alignment slot, configured to mate with asliding block on the fiber optic connector, is formed in the housing, soas to ensure the fiber optic connector is inserted into the fiber opticadapter in a correct orientation relative to the fiber optic adapter.

According to another exemplary embodiment of the present invention, whenthe alignment sleeve is adjusted to the predetermined circumferentialangle by the adjustment element, the first circumferential angle markand the second circumferential angle mark are aligned with the alignmentslot of the housing.

According to another exemplary embodiment of the present invention, thesecond circumferential angle mark of the mating retainer comprises anotch formed in the mating retainer; an foolproof assembly protrusion,configured to mate with the notch of the mating retainer, is formed onan inner wall of the housing; and the retainer is able to be assembledinto the housing only when the foolproof assembly protrusion of thehousing is aligned with the notch of the mating retainer.

According to another exemplary embodiment of the present invention, thefiber optic adapter further comprises a fixation element adapted to bemounted on the housing and hold a tube-like body of the mating retainer,so as to prevent the mating retainer from being pulled out of thehousing.

According to another exemplary embodiment of the present invention, thefiber optic adapter further comprises an elastic snapper mounted on thehousing and configured to lock the fiber optic adapter in a fixationinstallation position.

According to another exemplary embodiment of the present invention, themating retainer comprises a first mating retainer and a second matingretainer capable of being assembled together.

According to another exemplary embodiment of the present invention, thepositioning slot comprises a first positioning slot and a secondpositioning slot, aligned to each other, formed in mating ends of thefirst mating retainer and the second mating retainer, respectively.

According to another exemplary embodiment of the present invention, thesecond circumferential angle mark comprises a first notch and a secondnotch, aligned to each other, formed in the mating ends of the firstmating retainer and the second mating retainer, respectively.

According to another exemplary embodiment of the present invention, thefiber optic adapter is adapted to interconnect one or more pairs offiber optic connectors at the same time; one or more alignment sleeves,configured to align ferrules of one or more pairs of fiber opticconnectors, are received in the retainer.

According to another aspect of the present invention, there is providedan alignment sleeve assembly, comprising: an alignment sleeve adapted tobe received in a mating retainer of a fiber optic adapter; and anadjustment element configured to adjust a circumferential angle of thealignment sleeve relative to the mating retainer to a predeterminedcircumferential angle and hold the alignment sleeve at the predeterminedcircumferential angle relative to the mating retainer.

According to an exemplary embodiment of the present invention, theadjustment element is adapted to be sleeved on the alignment sleeve, anda radial protrusion is formed on an inner wall of the adjustment elementand adapted to be inserted into the longitudinal slot of the alignmentsleeve, so that the alignment sleeve is capable of being rotated withthe alignment element, and the circumferential angle of the alignmentsleeve relative to the mating retainer is capable of being adjusted byrotating the adjustment element.

According to another exemplary embodiment of the present invention, whenthe radial protrusion of the adjustment element is inserted into thelongitudinal slot of the alignment sleeve, the alignment sleeve isunable to be rotated in a circumferential direction relative to theadjustment element.

According to another exemplary embodiment of the present invention, whenthe radial protrusion of the adjustment element is inserted into thelongitudinal slot of the alignment sleeve, the alignment sleeve is onlyable to be rotated in a range of ±30 degrees in a circumferentialdirection relative to the adjustment element.

According to another exemplary embodiment of the present invention, whenthe radial protrusion of the adjustment element is inserted into thelongitudinal slot of the alignment sleeve, the alignment sleeve is onlyable to be rotated in a range of ±20 degrees in a circumferentialdirection relative to the adjustment element.

According to another exemplary embodiment of the present invention, whenthe radial protrusion of the adjustment element is inserted into thelongitudinal slot of the alignment sleeve, the alignment sleeve is onlyable to be rotated in a range of ±10 degrees in a circumferentialdirection relative to the adjustment element.

According to another exemplary embodiment of the present invention, theadjustment element is formed as a polygonal prism with a polygon crosssection;

According to another exemplary embodiment of the present invention, afirst circumferential angle mark, configured to identify thepredetermined circumferential angle of the alignment sleeve relative tothe mating retainer, is provided on an outer surface of the adjustmentelement.

In the above various exemplary embodiments of the present invention, theadjustment element is constructed to adjust the circumferential angle ofthe alignment sleeve with respect to the mating retainer to thepredetermined circumferential angle, for example, at which the fiberinsertion loss of the coupled connectors is minimal, and hold thealignment sleeve at the predetermined circumferential angle. In thisway, it may improve the alignment accuracy of the coupled connectors.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the present invention will become moreapparent by describing in detail exemplary embodiments thereof withreference to the accompanying drawings, in which:

FIG. 1 is an illustrative exploded view of a fiber optic adapteraccording to a first exemplary embodiment of the present invention;

FIG. 2 is an illustrative perspective view of an adjustment element ofthe fiber optic adapter of FIG. 1;

FIG. 3 is an illustrative perspective view of an alignment sleeve of thefiber optic adapter of FIG. 1;

FIG. 4 is an illustrative view of an alignment sleeve assembly formed byassembling the adjustment element of FIG. 2 to the alignment sleeve ofFIG. 3;

FIG. 5 is an illustrative view of a first circumferential angle markformed on an outer surface of the adjustment element of the alignmentsleeve assembly of FIG. 4;

FIGS. 6 and 7 are illustrative views of mounting the alignment sleeveassembly of FIG. 5 to a first mating retainer;

FIGS. 8 and 9 are illustrative views of assembling the first matingretainer of FIG. 7 to a second mating retainer;

FIG. 10 is an illustrative view of mounting the assembled first andsecond mating retainers of FIG. 9 to a housing;

FIG. 11 shows a foolproof installation structure between the housing andthe mating retainer;

FIG. 12 is an illustrative view of mounting an elastic snapper on thehousing;

FIG. 13 is an illustrative perspective view of the assembled fiber opticadapter according to the first exemplary embodiment of the presentinvention;

FIG. 14 is an illustrative perspective view of a fiber optic adapteraccording to a second exemplary embodiment of the present invention,wherein an alignment sleeve assembly is mounted to a first matingretainer;

FIG. 15 is an illustrative view of assembling the first mating retainerof FIG. 14 to a second mating retainer; and

FIG. 16 is an illustrative perspective view of an assembled fiber opticadapter according to a second exemplary embodiment of the presentinvention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Exemplary embodiments of the present disclosure will be describedhereinafter in detail with reference to the attached drawings, whereinthe like reference numerals refer to the like elements. The presentdisclosure may, however, be embodied in many different forms and shouldnot be construed as being limited to the embodiment set forth herein;rather, these embodiments are provided so that the present disclosurewill be thorough and complete, and will fully convey the concept of thedisclosure to those skilled in the art.

In the following detailed description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the disclosed embodiments. It will be apparent,however, that one or more embodiments may be practiced without thesespecific details. In other instances, well-known structures and devicesare schematically shown in order to simplify the drawing.

According to a general concept of the present invention, there isprovided a fiber optic adapter, comprising: a mating retainer; analignment sleeve received in the mating retainer, a ferrule of a fiberoptic connector being adapted to be inserted into the alignment sleevethrough an insertion port of the fiber optic adapter; and an adjustmentelement configured to adjust a circumferential angle of the alignmentsleeve relative to the mating retainer to a predeterminedcircumferential angle and hold the alignment sleeve at the predeterminedcircumferential angle relative to the mating retainer.

According to another general concept of the present invention, there isprovided an alignment sleeve assembly, comprising: an alignment sleeveadapted to be received in a mating retainer of a fiber optic adapter;and an adjustment element configured to adjust a circumferential angleof the alignment sleeve relative to the mating retainer to apredetermined circumferential angle and hold the alignment sleeve at thepredetermined circumferential angle relative to the mating retainer.

First Embodiment

FIGS. 1-13 show a fiber optic adapter according to a first exemplaryembodiment of the present invention.

FIG. 1 is an illustrative exploded view of the fiber optic adapteraccording to a first exemplary embodiment of the present invention.

As shown in FIG. 1, it shows a LC type of fiber optic adapter. The fiberoptic adapter mainly comprises a housing 100, a mating retainer 110,120, an alignment sleeve 130 and an adjustment element 140.

As shown in FIG. 1, the mating retainer 110, 120 comprises a firstmating retainer 110 and a second mating retainer 120 capable of beingassembled together. The mating retainer 110, 120 is configured toreceive the alignment sleeve 130 therein and lock coupled fiber opticconnectors (not shown) in place. A ferrule of one of the fiber opticconnector is adapted to be inserted into the alignment sleeve 130through an insertion port 101, 102 of the fiber optic adapter. In thisway, fiber cores of the fiber optic connectors are coupled with eachother in the alignment sleeve 130.

FIG. 2 is an illustrative perspective view of an adjustment element 140of the fiber optic adapter of FIG. 1; FIG. 3 is an illustrativeperspective view of an alignment sleeve 130 of the fiber optic adapterof FIG. 1; FIG. 4 is an illustrative view of an alignment sleeveassembly formed by assembling the adjustment element 140 of FIG. 2 tothe alignment sleeve 130 of FIG. 3.

As shown in FIGS. 1-4, in an embodiment, the adjustment element 140 isconfigured to adjust a circumferential angle of the alignment sleeve 130relative to the mating retainer 110, 120 to a predeterminedcircumferential angle and hold the alignment sleeve 130 at thepredetermined circumferential angle relative to the mating retainer 110,120.

In an embodiment, when the alignment sleeve 130 is held at thepredetermined circumferential angle relative to the mating retainer 110,120, an alignment error between fiber cores of fibers, which areinserted into the alignment sleeve 130 fiber optic adapter, of a pair offiber optic connectors is minimal, that is, an insertion loss isminimal. In this way, it is possible to minimize the insertion loss ofthe fiber optic connectors by adjusting and positioning thecircumferential angle of the alignment sleeve 130 with respect to themating retainer 110, 120.

In the first embodiment shown in FIGS. 1-13, only a single alignmentsleeve 130 is received in the mating retainer 110, 120. The alignmentsleeve 130 is configured to align ferrules of the pair of fiber opticconnectors to be coupled. Thereby, the fiber optic adapter of FIG. 1 isadapted to couple only a pair of fiber optic connectors at the sametime. However, the present invention is not limited to this; the fiberoptic adapter may be configured to couple a plurality of pairs of fiberoptic connectors at the same time.

Hereafter, it will describe in detail features and assembling operationof components of the optical fiber adapter with reference to drawings.

As shown in FIGS. 2-4, in an embodiment, the adjustment element 140 isadapted to be sleeved on the alignment sleeve 130. A radial protrusion141 is formed on an inner wall of the adjustment element 140 and adaptedto be inserted into a longitudinal slot 131 of the alignment sleeve 130,so that the alignment sleeve 130 is capable of being rotated with thealignment element 140, and the circumferential angle of the alignmentsleeve 130 relative to the mating retainer 110, 120 is adjusted byrotating the adjustment element 140.

In an exemplary embodiment of the present invention, the radialprotrusion 141 of the adjustment element 140 has a width in acircumferential direction equal to or slightly less than a width of thelongitudinal slot 131 of the alignment sleeve 130 in the circumferentialdirection. In this way, once the radial protrusion 141 of the adjustmentelement 140 is inserted into the longitudinal slot 131 of the alignmentsleeve 130, the alignment sleeve 130 is unable to be rotated in acircumferential direction relative to the adjustment element 140, or isonly able to be rotated in a very small angle range in thecircumferential direction relative to the adjustment element 140, forexample, is only able to be rotated in a range of ±30 degrees,preferably, in a range of ±20 degrees, more preferably, in a range of±10 degrees.

FIG. 5 is an illustrative view of a first circumferential angle mark 142a formed on an outer surface of the adjustment element 140 of thealignment sleeve assembly of FIG. 4.

As shown in FIGS. 4 and 5, in an embodiment, before the alignment sleeve130 is mounted to the mating retainer 110, 120, the alignment sleeve 130is adjusted to the optimum circumferential angle, at which the insertionloss of the optical fiber connectors is minimal, by the adjustmentelement 140.

FIGS. 6 and 7 are illustrative views of mounting the alignment sleeveassembly of FIG. 5 to the first mating retainer 110; FIGS. 8 and 9 areillustrative views of assembling the first mating retainer 110 of FIG. 7to the second mating retainer 120.

As shown in FIGS. 5-9, in an embodiment, after the alignment sleeve 130is adjusted to the optimum circumferential angle at which the insertionloss of the optical fiber connectors is minimal, a first circumferentialangle mark 142 a is provided on the outer surface 142 of the adjustmentelement 140. The first circumferential angle mark 142 a is used toidentify the optimum circumferential angle of the alignment sleeve 130relative to the mating retainer 110. In an embodiment, when thealignment sleeve 130 is adjusted to the optimum circumferential angle bythe adjustment element 140, the first circumferential angle mark 142 aof the adjustment element 140 should be aligned to a secondcircumferential angle mark 112, 122 formed on the mating retainer 110,120. In this way, during the alignment sleeve assembly of FIG. 5 ismounted to the mating retainer 110, 120, as long as the firstcircumferential angle mark 142 a of the adjustment element 140 isaligned to the second circumferential angle mark 112, 122 of the matingretainer 110, 120, it may ensure that the alignment sleeve 130 ispositioned at the optimum circumferential angle, at which the insertionloss of the optical fiber connectors is minimal, with respect to themating retainer 110.

In an exemplary embodiment of the present invention, as shown in FIGS.5-9, the adjustment element 140 is constructed as a polygonal prism witha polygon cross section exhibiting, for example, triangle,quadrilateral, pentagon, hexagon or any other shape with more edges. Inanother embodiment, the adjustment element 140 may have but not limitedto a regular polygon cross section. A positioning slot 111, 121,corresponding to an outer profile of the adjustment element 140, isformed in mating retainer 110, 120. The adjustment element 140 isadapted to be fixed in positioning slot 111, 121 of the mating retainer110, 120, so as to hold the alignment sleeve 130 at the optimumcircumferential angle relative to the mating retainer 110, 120.

Please be noted that the present invention is not limited to theillustrated embodiment, the adjustment element may be fixed on themating retainer by any other suitable way. For example, in anotherembodiment, the adjustment element 140 is formed with multiple splinekeys; the mating retainer 110, 120 is formed with multiple spline slots.The multiple spline keys of the adjustment element 140 are adapted to befitted in the multiple spline slots of the mating retainer 110, 120, soas to hold the alignment sleeve 130 at the optimum circumferential anglerelative to the mating retainer 110, 120.

FIG. 10 is an illustrative view of mounting the assembled first andsecond mating retainers 110, 120 of FIG. 9 to a housing 100.

As shown in FIGS. 9 and 10, after the first and second mating retainers110, 120 are assembled together, the entire mating retainer 110, 120 ismounted in the housing 100.

As shown in FIG. 10, in an embodiment, an alignment slot 103, configuredto mate with a sliding block (not shown) on the fiber optic connector,is formed in the housing 100, so as to ensure that the fiber opticconnector is inserted into the fiber optic adapter in a correctorientation relative to the fiber optic adapter. When the alignmentsleeve 130 is adjusted to and kept at the optimum circumferential angleby the adjustment element 140, the first circumferential angle mark 142a and the second circumferential angle mark 112, 122 are aligned to thealignment slot 103 of the housing 100. In this way, during the matingretainer 110, 120 is mounted to the housing 100, as long as the firstcircumferential angle mark 142 a and the second circumferential anglemark 112, 122 are aligned to the alignment slot 103 of the housing 100,it may ensure that the mating retainer 110, 120 is correctly mounted inthe housing 100.

FIG. 11 shows a foolproof installation structure between the housing 100and the mating retainer 110, 120.

As shown in FIG. 11, in an embodiment, in order to prevent the matingretainer 110, 120 from being incorrectly mounted to (for example,reversely mounted to) the housing 100, a foolproof installationstructure between the housing 100 and the mating retainer 110, 120 isdesigned.

As shown in FIG. 11, in an embodiment, the second circumferential anglemark 112, 122 of the mating retainer 110, 120 comprises a notch formedin the mating retainer 110, 120. A foolproof assembly protrusion 106,configured to mate with the notch of the mating retainer 110, 120, isformed on an inner wall of the housing 100. The mating retainer 110, 120is allowed to be assembled into the housing 100 only when the foolproofassembly protrusion 106 of the housing 100 is aligned to the notch ofthe mating retainer 110, 120. In other words, if the foolproof assemblyprotrusion 106 of the housing 100 is not aligned to the notch of themating retainer 110, 120, the retainer 110, 120 is not allowed to beassembled into the housing 100. In this way, it may effectively preventthe mating retainer 110, 120 from being incorrectly mounted to (forexample, reversely mounted to) the housing 100.

As shown in FIGS. 1 and 10, the fiber optic adapter may further comprisea fixation element 150 adapted to be mounted on the housing 100 and holda tube-like body 123 of the mating retainer 110, 120, so as to preventthe mating retainer 110, 120 from being pulled out of the housing 100.

In an embodiment, the fixation element 150 is inserted into the housing100 through a slot 105 (see FIG. 1) formed in the housing 100. Two legsof the fixation element 150 are inserted into two holes 104 formed inthe housing 100. As a result, the tube-like body 123 of the matingretainer 110, 120 is clamped and fixed by the fixation element 150.

FIG. 12 is an illustrative view of mounting an elastic snapper 160 onthe housing 100; FIG. 13 is an illustrative perspective view of theassembled fiber optic adapter according to the first exemplaryembodiment of the present invention.

As shown in FIGS. 12-13, in an embodiment, the fiber optic adapter mayfurther comprise an elastic snapper 160 mounted on the housing 100 andconfigured to lock the fiber optic adapter in a fixation installationposition.

In the first embodiment shown in FIGS. 1-13, the mating retainer 110,120 comprises the first mating retainer 110 and the second matingretainer 120 capable of being assembled together. The positioning slot111, 121 comprises a first positioning slot 111 and a second positioningslot 121, aligned to each other, formed in mating ends of the firstmating retainer 110 and the second mating retainer 120, respectively.The second circumferential angle mark 112, 122 comprises a first notch112 and a second notch 122, aligned to each other, formed in the matingends of the first mating retainer 110 and the second mating retainer120, respectively.

Also, it should be appreciated that, in some conditions, it isunnecessary to set the insertion loss of the fiber optic connectorsinserted into the fiber optic adapter to be minimal, but it is necessaryto maintain the longitudinal slot 131 of the alignment sleeve 130 at aspecified circumferential angle (a predetermined orientation) withrespect to the mating retainer 110, 120. In this case, it is alsopossible to use the adjustment element 130 to adjust the alignmentsleeve 130 to the specified circumferential angle and kept at thespecified circumferential angle.

Second Embodiment

FIGS. 14-16 show a fiber optic adapter according to a second exemplaryembodiment of the present invention.

FIG. 14 is an illustrative perspective view of a fiber optic adapteraccording to a second exemplary embodiment of the present invention,wherein an alignment sleeve assembly is mounted to a first matingretainer 210; FIG. 15 is an illustrative view of assembling the firstmating retainer 210 of FIG. 14 to a second mating retainer 220; and FIG.16 is an illustrative perspective view of an assembled fiber opticadapter according to a second exemplary embodiment of the presentinvention.

As shown in FIGS. 14-16, in the second embodiment, the fiber opticadapter is adapted to couple a plurality of pairs of fiber opticconnectors at the same time. A plurality of alignment sleeves 230,configured to align ferrules of the pairs of fiber optic connectors, arereceived in the mating retainer 210, 220.

Also, in the second embodiment shown in FIGS. 14-16, the fiber opticadapter does not comprise a housing, since the mating retainer 210, 220is served as a body of the fiber optic adapter and is directly exposedoutside.

In the second embodiment shown in FIGS. 14-16, the mating retainer 210,220 comprises a first mating retainer 210 and a second mating retainer220 capable of being assembled together. The mating retainer 210, 220 isconfigured to receive the alignment sleeves 130 therein and lock coupledfiber optic connectors (not shown) in place. A ferrule of a fiber opticconnector is adapted to be inserted into the alignment sleeve 230through an insertion port 201, 202 of the fiber optic adapter. In thisway, fiber cores of the fiber optic connectors are coupled with eachother in the alignment sleeve 230.

In the second embodiment shown in FIGS. 14-16, the adjustment element240 is configured to adjust a circumferential angle of the alignmentsleeve 230 relative to the mating retainer 210, 220 to a predeterminedcircumferential angle and hold the alignment sleeve 230 at thepredetermined circumferential angle relative to the mating retainer 210,220.

In the second embodiment shown in FIGS. 14-16, when the alignment sleeve230 is held at the predetermined circumferential angle relative to themating retainer 210, 220, an alignment error between fiber cores offibers, inserted into the alignment sleeve 130 fiber optic adapter, of apair of fiber optic connectors is minimal, that is, an insertion loss isminimal. In this way, it is possible to minimize the insertion loss ofthe fiber optic connectors by adjusting and positioning thecircumferential angle of the alignment sleeve 230 with respect to themating retainer 210, 220.

Hereafter, it will describe in detail features and operation ofassembling components of the optical fiber adapter with reference todrawings.

In the second embodiment shown in FIGS. 14-16, the adjustment element240 is adapted to be sleeved on the alignment sleeve 230. A radialprotrusion 241 is formed on an inner wall of the adjustment element 240and adapted to be inserted into a longitudinal slot 231 of the alignmentsleeve 230, so that the alignment sleeve 230 is capable of being rotatedwith the alignment element 240, and the circumferential angle of thealignment sleeve 230 relative to the mating retainer 210, 220 is capableof being adjusted by rotating the adjustment element 240.

In an exemplary embodiment of the present invention, the radialprotrusion 241 of the adjustment element 240 has a width in acircumferential direction equal to or slightly less than a width of thelongitudinal slot 231 of the alignment sleeve 230 in the circumferentialdirection. In this way, once the radial protrusion 241 of the adjustmentelement 240 is inserted into the longitudinal slot 231 of the alignmentsleeve 230, the alignment sleeve 230 is unable to be rotated in thecircumferential direction relative to the adjustment element 240, or isonly able to be rotated in a very small angle range in thecircumferential direction relative to the adjustment element 240, forexample, is only able to be rotated in a range of ±30 degrees,preferably, in a range of ±20 degrees, more preferably, in a range of±10 degrees.

In the second embodiment shown in FIGS. 14-16, before the alignmentsleeve 230 is mounted to the mating retainer 210, 220, the alignmentsleeve 230 is adjusted to the optimum circumferential angle, at whichthe insertion loss of the optical fiber connectors is minimal, by theadjustment element 240.

In the second embodiment shown in FIGS. 14-16, after the alignmentsleeve 230 is adjusted to the optimum circumferential angle at which theinsertion loss of the optical fiber connectors is minimal, a firstcircumferential angle mark 242 a is provided on the outer surface 242 ofthe adjustment element 240. The first circumferential angle mark 242 ais used to identify the optimum circumferential angle of the alignmentsleeve 230 relative to the mating retainer 210. In an embodiment, whenthe alignment sleeve 230 is adjusted to the optimum circumferentialangle by the adjustment element 240, the first circumferential anglemark 242 a of the adjustment element 240 should be aligned to a secondcircumferential angle mark 212, 222 formed on the mating retainer 210,220. In this way, during the alignment sleeve assembly of FIG. 14 ismounted to the mating retainer 210, 220, as long as the firstcircumferential angle mark 242 a of the adjustment element 240 isaligned to the second circumferential angle mark 212, 222 of the matingretainer 210, 220, it may ensure that the alignment sleeve 230 ispositioned at the optimum circumferential angle, at which the insertionloss of the optical fiber connectors is minimal, with respect to themating retainer 210, 220.

In the second embodiment shown in FIGS. 14-16, the adjustment element240 is constructed as a polygonal prism with a polygon cross sectionexhibiting, for example, triangle, quadrilateral, pentagon, hexagon orany other shape with more edges. In another embodiment, the adjustmentelement 240 may have but not limited to a regular polygon cross section.A positioning slot 211, 221, corresponding to an outer profile of theadjustment element 240, is formed in mating retainer 210, 220. Theadjustment element 240 is adapted to be fixed in positioning slot 211,221 of the mating retainer 210, 220, so as to hold the alignment sleeve230 at the optimum circumferential angle relative to the mating retainer210, 220.

Please be noted that the present invention is not limited to theillustrated embodiment, the adjustment element may be fixed on themating retainer by any other suitable way. For example, in anotherembodiment, the adjustment element 240 is formed with multiple splinekeys; the mating retainer 210, 220 is formed with multiple spline slots.The multiple spline keys of the adjustment element 240 are adapted to befitted in the multiple spline slots of the mating retainer 210, 220, soas to hold the alignment sleeve 230 at the optimum circumferential anglerelative to the mating retainer 210, 220.

In the second embodiment shown in FIGS. 14-16, the secondcircumferential angle mark 212, 222 of the mating retainer 210, 220 is anotch formed in the mating retainer 210, 220.

In the second embodiment shown in FIGS. 14-16, the mating retainer 210,220 comprises a first mating retainer 210 and a second mating retainer220 capable of being assembled together. The positioning slot 211, 221comprises a first positioning slot 211 and a second positioning slot221, aligned to each other, formed in mating ends of the first matingretainer 210 and the second mating retainer 220, respectively. Thesecond circumferential angle mark 212, 222 comprises a first notch 212and a second notch 222, aligned to each other, formed in the mating endsof the first mating retainer 210 and the second mating retainer 220,respectively.

The first mating retainer 210 and the second mating retainer 220 arecoupled with each other in a snap-fit manner. In an exemplaryembodiment, the first mating retainer 210 is provided with a pluralityof first engagement protrusions 251 and a plurality of first engagementrecesses 252, and the second mating retainer 220 is provided with aplurality of second engagement protrusions 253, which are engaged withthe plurality of first engagement recesses 252, respectively, and aplurality of second engagement recesses 254, which are engaged with theplurality of first engagement protrusions 252, respectively.Furthermore, the first mating retainer 210 is provided with at least onefirst guiding protrusions 255 and at least one first guiding recesses256, and the second mating retainer 220 is provided with at least onesecond guiding protrusions, which are engaged with the plurality offirst engagement recesses 256, respectively, and at least one secondguiding recesses, which are engaged with the plurality of firstengagement protrusions 255, respectively.

Also, it should be appreciated that, in some conditions, it isunnecessary to set the insertion loss of the fiber optic connectorsinserted into the fiber optic adapter to be minimal, but it is necessaryto maintain the longitudinal slot 231 of the alignment sleeve 1230 at aspecified circumferential angle (a predetermined orientation) withrespect to the mating retainer 210, 220. In this case, it is alsopossible to use the adjustment element 230 to adjust the alignmentsleeve 230 to the specified circumferential angle and kept at thespecified circumferential angle.

It should be appreciated for those skilled in this art that the aboveembodiments are intended to be illustrated, and not restrictive. Forexample, many modifications may be made to the above embodiments bythose skilled in this art, and various features described in differentembodiments may be freely combined with each other without conflictingin configuration or principle.

Although several exemplary embodiments have been shown and described, itwould be appreciated by those skilled in the art that various changes ormodifications may be made in these embodiments without departing fromthe principles and spirit of the disclosure, the scope of which isdefined in the claims and their equivalents.

As used herein, an element recited in the singular and proceeded withthe word “a” or “an” should be understood as not excluding plural ofsaid elements or steps, unless such exclusion is explicitly stated.Furthermore, references to “one embodiment” of the present invention arenot intended to be interpreted as excluding the existence of additionalembodiments that also incorporate the recited features. Moreover, unlessexplicitly stated to the contrary, embodiments “comprising” or “having”an element or a plurality of elements having a particular property mayinclude additional such elements not having that property.

What is claimed is:
 1. A fiber optic adapter, comprising: a matingretainer; an alignment sleeve received in the mating retainer, a ferruleof a fiber optic connector being adapted to be inserted into thealignment sleeve through an insertion port of the fiber optic adapter;and an adjustment element configured to adjust a circumferential angleof the alignment sleeve relative to the mating retainer to apredetermined circumferential angle and hold the alignment sleeve at thepredetermined circumferential angle relative to the mating retainer. 2.The fiber optic adapter according to claim 1, wherein when the alignmentsleeve is held at the predetermined circumferential angle relative tothe mating retainer, an alignment error between fiber cores of fibers,inserted into the alignment sleeve of the fiber optic adapter, of a pairof fiber optic connectors is minimal.
 3. The fiber optic adapteraccording to claim 1, wherein when the alignment sleeve is held at thepredetermined circumferential angle relative to the mating retainer, alongitudinal slot in the alignment sleeve is positioned at apredetermined orientation.
 4. The fiber optic adapter according to claim2, wherein the adjustment element is adapted to be sleeved on thealignment sleeve, and a radial protrusion is formed on an inner wall ofthe adjustment element and adapted to be inserted into the longitudinalslot of the alignment sleeve, so that the alignment sleeve is rotatablewith the alignment element, and the circumferential angle of thealignment sleeve relative to the mating retainer is adjustable byrotating the adjustment element.
 5. The fiber optic adapter according toclaim 4, wherein when the radial protrusion of the adjustment element isinserted into the longitudinal slot of the alignment sleeve, thealignment sleeve is limited to be rotated in a circumferential directionrelative to the adjustment element.
 6. The fiber optic adapter accordingto claim 4, wherein when the radial protrusion of the adjustment elementis inserted into the longitudinal slot of the alignment sleeve, thealignment sleeve is limited to be rotated in a range of ±30 degrees in acircumferential direction relative to the adjustment element.
 7. Thefiber optic adapter according to claim 4, wherein when the radialprotrusion of the adjustment element is inserted into the longitudinalslot of the alignment sleeve, the alignment sleeve is limited to berotated in a range of ±20 degrees in a circumferential directionrelative to the adjustment element.
 8. The fiber optic adapter accordingto claim 4, wherein when the radial protrusion of the adjustment elementis inserted into the longitudinal slot of the alignment sleeve, thealignment sleeve is limited to be rotated in a range of ±10 degrees in acircumferential direction relative to the adjustment element.
 9. Thefiber optic adapter according to claim 4, wherein the adjustment elementis formed as a polygonal prism with a polygon cross section; wherein apositioning slot, corresponding to an outer profile of the adjustmentelement, is formed in the mating retainer; and wherein the adjustmentelement is adapted to be fixed in the positioning slot of the matingretainer, so as to hold the alignment sleeve at the predeterminedcircumferential angle relative to the mating retainer.
 10. The fiberoptic adapter according to claim 4, wherein the adjustment element isformed with multiple spline keys, and the mating retainer is formed withmultiple spline slots; and wherein the multiple spline keys of theadjustment element are adapted to be fitted in the multiple spline slotsof the mating retainer, so as to hold the alignment sleeve at thepredetermined circumferential angle relative to the mating retainer. 11.The fiber optic adapter according to claim 9, wherein a firstcircumferential angle mark is provided on an outer surface of theadjustment element, and a second circumferential angle mark is providedon the mating retainer; and when the alignment sleeve is adjusted to thepredetermined circumferential angle by the adjustment element, the firstcircumferential angle mark of the adjustment element is aligned with thesecond circumferential angle mark of the mating retainer.
 12. The fiberoptic adapter according to claim 11, further comprises a housing inwhich the mating retainer are mounted; and wherein an alignment slot,configured to mate with a sliding block on the fiber optic connector, isformed in the housing, so as to ensure the fiber optic connector isinserted into the fiber optic adapter in a correct orientation relativeto the fiber optic adapter.
 13. The fiber optic adapter according toclaim 12, when the alignment sleeve is adjusted to the predeterminedcircumferential angle by the adjustment element, the firstcircumferential angle mark and the second circumferential angle mark arealigned with the alignment slot of the housing.
 14. The fiber opticadapter according to claim 13, wherein the second circumferential anglemark of the mating retainer comprises a notch formed in the matingretainer; wherein an foolproof assembly protrusion, configured to matewith the notch of the mating retainer, is formed on an inner wall of thehousing; and wherein the mating retainer is assembled into the housingonly when the foolproof assembly protrusion of the housing is alignedwith the notch of the mating retainer.
 15. The fiber optic adapteraccording to claim 12, further comprises a fixation element adapted tobe mounted on the housing and hold a tube-like body of the matingretainer, so as to prevent the mating retainer from being pulled out ofthe housing.
 16. The fiber optic adapter according to claim 12, furthercomprises an elastic snapper mounted on the housing and configured tolock the fiber optic adapter in a fixation installation position. 17.The fiber optic adapter according to claim 9, wherein the matingretainer comprises a first mating retainer and a second mating retainerbeing assembled together.
 18. The fiber optic adapter according to claim17, wherein the positioning slot comprises a first positioning slot anda second positioning slot, aligned to each other, formed in mating endsof the first mating retainer and the second mating retainer,respectively.
 19. The fiber optic adapter according to claim 18, whereinthe second circumferential angle mark comprises a first notch and asecond notch, aligned to each other, formed in the mating ends of thefirst mating retainer and the second mating retainer, respectively. 20.The fiber optic adapter according to claim 1, wherein the fiber opticadapter is adapted to interconnect one or more pairs of fiber opticconnectors at the same time; and wherein one or more alignment sleeves,configured to align ferrules of one or more pairs of fiber opticconnectors, are received in the retainer.
 21. An alignment sleeveassembly, comprising: an alignment sleeve adapted to be received in amating retainer of a fiber optic adapter; and an adjustment elementconfigured to adjust a circumferential angle of the alignment sleeverelative to the mating retainer to a predetermined circumferential angleand hold the alignment sleeve at the predetermined circumferential anglerelative to the mating retainer.
 22. The alignment sleeve assemblyaccording to claim 21, wherein the adjustment element is adapted to besleeved on the alignment sleeve, and a radial protrusion is formed on aninner wall of the adjustment element and adapted to be inserted into thelongitudinal slot of the alignment sleeve, so that the alignment sleeveis rotatable with the alignment element, and the circumferential angleof the alignment sleeve relative to the mating retainer is adjustable byrotating the adjustment element.
 23. The alignment sleeve assemblyaccording to claim 22, when the radial protrusion of the adjustmentelement is inserted into the longitudinal slot of the alignment sleeve,the alignment sleeve is limited to be rotated in a circumferentialdirection relative to the adjustment element.
 24. The alignment sleeveassembly according to claim 22, when the radial protrusion of theadjustment element is inserted into the longitudinal slot of thealignment sleeve, the alignment sleeve is limited to be rotated in arange of ±30 degrees in a circumferential direction relative to theadjustment element.
 25. The alignment sleeve assembly according to claim22, when the radial protrusion of the adjustment element is insertedinto the longitudinal slot of the alignment sleeve, the alignment sleeveis limited to be rotated in a range of ±20 degrees in a circumferentialdirection relative to the adjustment element.
 26. The alignment sleeveassembly according to claim 22, when the radial protrusion of theadjustment element is inserted into the longitudinal slot of thealignment sleeve, the alignment sleeve is limited to be rotated in arange of ±10 degrees in a circumferential direction relative to theadjustment element.
 27. The alignment sleeve assembly according to claim23, wherein the adjustment element is formed as a polygonal prism with apolygon cross section;
 28. The alignment sleeve assembly according toclaim 27, wherein a first circumferential angle mark, configured toidentify the predetermined circumferential angle of the alignment sleeverelative to the mating retainer, is provided on an outer surface of theadjustment element.